“We are desperate for the truth, and hope that the upcoming inquest will provide the answers that the IOPC have been unable to deliver,” he added.

An IOPC spokesman said in response that the five officers involved attended an interview and provided written statements.

Edson, 25, died in hospital six days after being stopped in a car by police in Tollgate Road, Beckton, on June 15 last year.

The investigation found that before or during the stop, he had tried to swallow bags found to contain crack cocaine and heroin.

Edson Da Costa. Picture: submitted

He lost consciousness while being handcuffed. An officer may have committed misconduct after using CS spray on him at the same time of his arrest, the IOPC found.

The watchdog concluded today (October 30) that police were justified in stopping the Mercedes hire car.

The charity Inquest, which advises on state-related deaths, has contacted IOPC director general Michael Lockwood raising concerns that the watchdog revealed information before an inquest due next year.

Victoria McNally, a caseworker for Inquest, said: “It is unprecedented for the IOPC to issue a statement ahead of an inquest hearing into a police death.

“We believe the IOPC has gone beyond the needs of transparency and has strayed into evidence and findings that should be the responsibility and domain of the inquest process.

“Families are repeatedly warned not to disclose information in advance of an inquest to avoid prejudice.”

Susie Labinjoh, partner at law firm Hodge Jones and Allen, which represents the family, said: “The family believe it was misguided of the IOPC to issue such a press release given that the inquest is yet to take place.

She added that the firm will be looking to the inquest to provide full scrutiny of the circumstances into Edson’s death. “We hope that the truth will be revealed at the inquest so the family is able to grieve properly,” Ms Labinjoh said.